Soil penetrometer



SRUSS REEERE'HZE April 23, 1968 A. HOWARD ETAL SOIL PENETROMETER FiledSept. 20. 1965 5 Sheets-Sheet 1 INVENTORS. 154F14 4 .A/fiWflEfl 650,66544 6 07 BY 55567 A6,? in

SLAKEBE was April 23. 1968 E. A. HOWARD ETAL SOIL PENETROMETER 2 W X a Zm 7/. w w w A M WW w a. v 523:; W :ZL w mw AAA. Qb fi v. W T a L K 7 Q5,i My, y, M mm w W i w A H f% SOIL PENETROMETER 5 Sheets-Sheet- 3 FiledSept- 20, .1965

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United States Patent Office Patented Apr. 23, 1968 SOIL PENETROMETEREarle A. Howard, 4321 Beulah Drive, La Canada, Calif.

91011; George M. Hotz, 1564 Gaywood Drive, Altadena, Calif. 91001; andRobert P. Bryson, 2616 N.

Upland St., Arlington, Va. 22207 Filed Sept. 20, 1965, Ser. No. 488,38416 Claims. (CI. 73-81) This invention relates to devices for burrowinginto soil formations and, more particularly, to an auger-type soilpenetrometer.

The invention described herein was made in the performance of work underNASA contract and is subject to the provisions of the NationalAeronautics and Space Act of 1958, Public Law 85468 (72. Stat. 42/6; 42U.S.C. 2451), as amended.

Augerstype soil penetrometers are known. Existing auger-typepenetrometers have the common characteristic that theauger is coupled tothe lower end of a substantially rigid rotatable member or drive shaft.In view of the rigidity of .the drive shaft, the auger. can be movedonly along a line corresponding to the initial direction of the shaft atthe surface of the soil. Accordingly, such penetrometers can be used toobtain soil characteristic 1 measurements only to the depth to which theauger can be driven along a substantially straight line. If the augershould encounter a buried boulder, for example, the rigidity of thedrive shaft does not permit the auger to deviate from its basicpredetermined path.

This invention provides a soil penetrometer which has the feature thatthe auger, while initially moving along a predetermined path, maydeviate from such path when the auger encounters a buried'boulder or thelike. Accordingly, the depth to which this penetrometer may be used isnot limited by the existence of buried boulders and other localimpediments to the movement of the auger through the soil. Moreover, thepenetrometer is not re-' stricted to deriving soil characteristic datasolely from the torque required to drive the auger. Accordingly,

creased information about the soil through which the auger.

moves may be obtained.

Generally speaking, this invention provides apparatus for burrowing intothe earth. The apparatus includes an elongate coila-ble torquetransmitting member and coiling means for the torque transmitting memberat one end of the member. An anger is connected to the other end of thetorque transmitting member so as to be driven in response to rotation ofthe torque transmitting member. A base is also provided. Support meansfor the coiling means are mounted to the base for rotation relative tothe base. The torque transmitting member extends from the coiling meansto the auger along the axis about which the support means is rotatablerelative to the base. The apparatus also includes drive means coupledtothe sup port means operable to rotate the support means about saidaxis to rotate the torque transmitting member, thereby to drive theauger.

The above-mentioned and other features of the present invention are morefully set forth in the following detailed description of the invention,which descriptionis presented in conjunction with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional elevation view of a soil penetrometeraccording to this invention;

FIG. 2 is an elevation view, with parts omitted, taken along line 2-2 ofFIG. 1;

FIG. 3 is a cross-sectional elevation view of another soil penetrometeraccording to this invention;

FIG. 4 is a cross-sectional elevation view taken along lines 4-4 of FIG.3:. and

FIG. 5 is a cross-sectional. elevation view" taken along lines- 55 ofFIG. 3.

1 shows a soil penetrometer 10, the penetrometer comprising a presentlypreferred embodiment of this invention. The penetrometer includes a base11 having a horizontal portion 12 engaged with the surface of a soilformation 13 in whichmeasurements of soil characteristics are to bemade. The base member also has a vertical portion 14. The groundengaging portion of the base meni'ber is open at 15 to permit thepassage of anger 23 into the soil formation. I

An elongated, flexible and coilable torque transmission shaft 18 has oneof its ends connected to a rotatable drum 19. The flexible shaftpreferably is constructed of several concentric, tightly wound wirecoils, alternate coils being wound in opposite directions as shown inFIG. 5 relative to shaft 74. Such flexible torque transmitting shaftsare known and, therefore, shaft 18 is not illustrated in greater detail.Drum 19 defines a single helical groove 20 around and along its exteriorsurface to receive substantially the entire length of the flexibleshaft. The drum comprises coiling means for the flexible shaft.

The flexible shaft passes from drum 19 through openingI'S to the upperend of the body 22 of an auger 23 having a helical auger blade 24secured to and wound around the exterior of the auger body. The lowerend of the auger body is pointed. The auger is constructed so that iteither advances through, or retracts itself from, soil with which it isengaged, depending upon the direction of rotation of flexible shaft 18.

Shaft coiling and storage drum 19 is mounted on a horizontally disposedshaft 25. The drum is mounted to the shaft so that the drum and shaftrotate together and so that the-drum may move axially along the shaft.Axial movement of the drum along shaft 25 is produced by the cooperationof flexible shaft 18 with helical grooves 20 as -the .drum is rotated toreel in or pay out the flexible shaft in accord with axial movement ofthe auger.

The drum is rotatably mounted at its opposite ends in a support member26. The support member is in turn rotatably mounted in a frame 27 which.is mounted in cantilever fashion to the vertical portion of base 11. Thesupport member has upper and lower axles 28 and 29, respectively, whichare rotatably mounted to the frame. The support member axles are alignedalong a vertical axis 30 about which the support member is rotatablerelative to the base. Axle 29 is axially bored at 31 so that theflexible shaft 18 may be passed through it to :the auger. A guide tube32 for the flexible shaft is mounted to the lower axle and extends frombore 31 into substantial tangency with drum 19 to guide the flex ibleshaft into registry with groove 20. 1

Frame 27 is mounted to base 11 at its upper end by a link 34 pivotallyconnected at its opposite .ends to the frame and to the base member,respectively. The frame is mounted at its lower end to the base by aflexure arm 35. One end of the flexure arm is pivotally connected to theframe; the other end of the flex-ure arm is rigidly connected to thebase. The frame thus is mounted to the base for limited movement alongaxis 30. The frame is further supported on the base by a spring 36engaged between the frame and base portion 12. The spring urges theframe into a selected position along the axis in which flexure arm 35 isrelatively unstressed. The spring is disposed around a telescoping postassembly 37 which prevents buckling of the spring.

Penetrometer 10 includes means for rotating the sup port member relativeto the base. A motor plate 39 is rotatably mounted to support memberaxle 29'v above the lower extent of the frame. An electric motor 40 ismounted to the motor plate and depends through an opening 41 in theframe. The .motor has an upwardly extending output shaft 42 to which apinion gear 43 is :secured for engagement with a spur gear 44 which is:secured to axle 29 above the motor plate. The motor plate is heldsubstantially stationary relative to the frame by a force gage assembly45. Force gage assembly 45 is similar to the gage structure shown inFIG. 4 and permits only slight relative movement between the motor plateand the frame. The force gage assembly, however, includes a pair ofsprings (not shown) which urge the motor plate into a normal orreference position angularly relative to the frame. The force gageassembly is provided to continuously measure the torque imparted toflexible shaft 18 to drive the auger in response to rotation of thesupport member. Operation of motor 40 produces rotation of supportmember 26 about axis 30 so that the flexible shaft is rotated to drivethe auger.

Soil penetrometer also includes means for reeling the flexible shaft toand from drum 19 and for maintaining the flexible shaft in tension asthe auger is rotated. An electric motor 46 is mounted to the drumsupport member below the drum. The motor has a rotatable output shaft(not shown) which extends horizontally parallel to shaft 25. The motoroutput shaft comprises th input shaft of a friction-type adjustable slipclutch 47 which has a rotatable, horizontally extending output shaft 48.A pinion gear is secured to shaft 48 and is engaged with a spur gear 49secured to drum shaft 25.

As the flexible shaft is rotated by opertaion of motor 40 to advance theauger through soil formation 13, the flexible shaft is urged to unreelfrom drum 19 at the same rate at which the auger advances. Motor 46 isoperated to rotate drum 19 in the direction of flexible shaft payout,but at a rate which, if the drum were positively linked to the motor,would drive the drum at a slower rate. The torque imposed upon the drumby motor 46 via slip clutch 47, however, is less than the torque imposedupon the drum by the tension in the flexible shaft. Accordingly, theclutch slips and shaft 48 overruns the motor shaft. The slip clutch,however, imposes a drag upon the drum so that the flexible shaft is keptunder tension as the auger is advanced. The amount of the drag imposedupon the drum is determined by the adjustment of the slip clutch. It isdesired that tension be maintained on the flexible shaft as the auger isadvanced to provide a guiding drag upon the auger and to prevent theflexible shaft from twisting itself .into knots as a result of thetorque developed in it.

Tension is also maintained in the flexible shaft when the flexible shaftis rotated in the opposite direction to recover the auger. In this case,tension is desired to provide a guiding pull on the auger and to preventthe shaft from twisting itself into knots. When the auger is beingrotated to cause it to back out of soil formation 13, drum drive motor46 is operated to cause the drum to reel in the flexible shaft. Motor 46is operated at a rate which, but for slip clutch 47, would cause theflexible shaft to be reeled in at a rate greater than the rate ofmovement of the auger. The slippage provided by the slip clutch,however, permits the drum to reel in the flexible shaft at the rate atwhich the auger burrows out of the soil formation. The setting of theslip clutch determines the amount of tension imposed upon the flexibleshaft.

Penetrometer 10 is instrumented so that measurements of thecharacteristics of the soil through which the auger passes may beobtained. As noted above, a force gage assembly 45 is coupled to motorplate 39 for measuring the torque imparted to the auger; it will beunderstood, however, that the torque delivered to the auger may bemeasured at the auger, if desired. The penetrometer also includes meansfor measuring the tension in the flexible shaft. A pair of electricalstrain gages 51 are bonded to the upper and lower surfaces,respectively, of flexure member 35. As noted above. frame 27 has apredetermined position relative to base 11 in which the flexure memberor at l ast the s rain gages secur d to the flexure member, areunstressed. When the auger is engaged with the soil formation andtension is imparted to the flexible shaft, the frame is moved toward thebase and the flex= ure member is deformed. The deformation of theflexure member is proportional to the tension in the flexible shaft. Thestrain gages, therefore, comprise a means for measuring this tension.

The penetrometer also includes means for relating the measurements oftorque delivered to the auger and of tension in the flexible shaft tothe position of the auger in the soil formation. A multi-turnpotentiometer 54 is coupled to One end of drum shaft 25. The output ofthe potentiometer is directly related to the amount of flexi- 'ble shaftpayed-out from the drum and thus is a measure of the position of theauger in the soil formation. Frame axle 28 carries three slip rings 5 towhich are connected, respectively, the opposite ends of thepotentiometer wiper. The slip rings cooperate with Wiper brushes whichextend from a supporting housing 56 mounted to frame 27. Axle 28 alsocarries slip rings 57 by which electrical power is supplied to motor 46.

To assure that auger 23 is properly engaged with soil formation 13 asoperation of penetrometer 10 is commenced, an auger guide assembly 59 ismounted to sup port member 26. The auger guide assembly includes ahollow tube 60 secured to the lower end of support member axle 29 belowframe 27. Tube 60 is disposed concentric to axis 30 and has an openlower end defining an inwardly extending peripheral flange 61. A hollowtube 62 is slidably mounted in tube 60 for telescoping move ment alongaxis 30 relative to tube 60. Tube 61 has an outwardly extendingcircumferential flange 63 at its upper end which is engageable withflange 61 to prevent disengagement of the tubes. The inner diameter ofthe inner tube is sized to receive the upper end of auger body 22. Inthe drawing the distance between frame 27 and base portion 12 has beenforeshortened for purposes of compactness of illustration; workersskilled in the art will appreciate that the penetrometer is constructedso that the pointed lower end of the auger lies above the bottom surfaceof the base when the auger is fully retracted.

Another soil penetrometer 70 according to this inven-- tion is shown inFIGS. 3-5. The penetrometer includes a base 71 (similar to base 11), aframe 72 (similar to frame 27), and a support member 73. Thepenetrometer also includes an elongated, flexible and coilable torquetransmission shaft 74 which is like shaft 18., One end of the flexibleshaft is connected to a shaft storage and reeling cage 75 and the otherend of the flexible shaft is secured to the upper end of an auger (notshown but like auger 23).

Cage 75 is hollow and has a conical lower end 76 and a cylindrical upperend 77. Shaft 74 is connected to the cage so that as the cage is rotatedabout a vertical axis 78 of the penetrometer, the shaft is coiled aroundthe interior of the upper end of the cage. The cage is secured tosupport member 73 so that the cage is mounted for rotation with thesupport member relative to the base.

The support member has a downwardly extending axially bored :axle 79which is rotatably mounted to frame 72 concentric to axis 78. The upperend of the cage is rotatably mounted to the frame along the axis by apotentiometer housing 80 secured to the upper end of the cage and by ashaft 81 engaged between'the frame and the housing. The frame, in turn,is mounted to the base for limited axial movement along axis 78 by alink 34, a flexure member 35 and a spring 36. The base defines anopening 15 through it along axis 78 so that the auger may be engagedwith soil formation 13 on which the base is supported.

Adjacent the lower end of cage 75, the support mem= ber carries a spurgear 83 concentric to axis 78. The spur gear is engaged with a worm gear84 (see FIG. 4) which is mounted to the output shaft 85 of an electricmotor 86. Motor 86 is mounted to a motor plate 92. Shaft 85 at oppositeends of the Worm gear is mounted in. bearings 87 which are carried themotor plate. Operation of the motor rotate, the support member and thecage about axis 78 so that. the flexible is rotated to drive the auger,

Penetrometer 70, like penetromeiier 10, includes a force gage assembly90 for measuring the torque iru parted to flexible shaft 18 to drive theauger, The hear ing which journals the end. of shaft 85 opposite frommotor 86 is mounted by a pedestal 91 to motor plate 92 which isslidably' mounted to the frame, by a dove= tail connection, for example,for linear movement. T613, tive to the frame in. the plane of spur gearMotor 86 is also mounted to the motor plate: Intermediate the bearingand the motor plate, pedestal 91 defines a hole 93 through it parallelto the line of movement of the motor plate relative to the frame, A.guide pin 94 is passed through hole 93 and is mounted-at its oppositeends to respective ones of a pair of brackets 95 which. are fixed toframe 72, A compression spring 96 is disposed around pin 94 between thepedestal. and each bracket, The springs urge the motor plate into aselected position relative to the frame. The motor plate carries thearma= ture 97 of a differential transformer 98 which has its primarywinding 99 and its secondary windings 100 fixed relative to the frame:Depending upon the'amount and direction of the torque imparted totheiflexible shaft by operation of motor 86, the motor plate moves inone direction or the other relative to the frame from the normalposition of the motor plate, This movement: proportional to the torquewhich is delivered to the auger, The output of the differentialtransformer, there= fore, is a measure of this torque Workers skilled inthe art to which this invention re= lates will appreciate that somemechanism other than a differential transformer may be used to measurethe torque delivered to the auger, if desired, For example, strain gagesmay be used in conjunction with a strain member coupled between themotor plate and the frame, Alternatively, motor 86 may be fixed directlyto the frame and the power required to operatethe motor at a given.speed may be used as a measure of the torque delivered to the auger, Theuse of a differential transformer has been described and shown merelyfor the purposes of illustration and. example,

Penetrometer 70 also includes means for reeling the flexible shaft toand from cage 75 and for maintaining the flexible shaft in tension asthe auger is rotated so that the maximum torque transmitting capacity ofthe flexible shaft utilized, A drive pulley 104 for the flexible shaftdisposed in a chamber-1.05 in. support: member 73 so that the drivepulley is oriented in a plane parallel to axis 78 and is engaged withthe flexible shaft. along the length. thereof which. passes through anaxial bore 106 through the support member. The pulley co operates withan idler wheel 107 which. is rotatably mounted in chamber 1.05 forengagement. withv the side of the flexible shaft opposite from the drivepulley, drive pulley is secured to a shaft. 108 which is the outputshaft of a friction-type slip clutch device 109, The slip clutch has asits input the rotatable output shaft (not shown) of an electric motor110 (see FIG, 5)., Motor 110 is operated to drive pulley 104 m the samemanner that motor 46 is operated to drive drum. 19 to maintain tensionin flexible shaft 74, regardless of the direction. of rotation. of theflexible shaft and regardless of the direction. of movement of theflexible shah. through bore 106,

An auger receiver and guide assembly 59, in accord with the foregoingdescription, is secured to the lower end of support member 73 belowframe 72 concentric to axis 78 A. strain gage 51 is bonded to each ofthe upperand. lower surfaces of flexure member 35 for measuring thetension imposed upon flexible shaft 74.

The instantaneous depth of the anger in soil formation 13 is measured bythe output of a. multi-turn potentiometer 110 which. is mounted withinhousing to the upper end of cage 75 concentric to axis 78 for rotationwith the cage, The wiper of the potentiometer is connected to arotatable shaft 111 which extends from the potentiometer into the cagealong axis 78, A flexible shaft follower arm 112 is connected to theshaft in the cage for rotation with the shaft. The follower arm isengaged with the flexible shaft, As the flexible shaft is reeled into orout of the cage, even during rotation of the cage to rotate the flexibleshaft, the follower arm, by reason of its engagement with the flexibleshaft, is rotated relative to the cage. Since the flexible shaft iscoiled for storage within the cylindrical upper end of the cage, therotation of shaft 111 is directly related to the depth of the auger inthe soil formation. Thus, the output of potentiometer is a measure ofthe depth of the auger,

Three slip rings 114 are mounted to the exterior of housing 80 andcooperates with a like number of brushes 115 which extend from a brushholder 116 mounted to the upper end of frame 72. Respective ones of sliprings 114 areconductively connected by Wires (not shown) to the oppositeends of the potentiometer winding and to the potentiometer wiper. Threeadditional slip rings r 11.7 are mounted to housing 80 for coopertaionwith a like number of brushes 118; these slip rings are conductivclyconnected to the input terminals of motor 110,

Penetrometers 10 and 70 are operated in similar manners to obtain datafrom which certain characteristics of soil formation 13 may be inferred.The penetrometer is disposed over a desired location of the soilformation; as noted above, at this time the auger is fully retracted sothat its lower end is above the bottom surface of penetrometer base 11.Motors 40 and 46 (or motors 86 and 110) are operated to rotate thflexible shaft and to pay the flexible shaft from its coiling means. Asthe flexible shaft is payed out, auger receiver and guide assembly 59guides the auger along axis 30 (or axis 78) into engagement with thesoil formation, The auger is kept in contact with the guide assemblylong enough to assure that the auger commences its movement through thesoil formation along an imaginary extension of the axis of rotation ofthe support member; thereafter the drag or tension in the flexible shaftserves to maintain the auger along such a path until a buried boulder orthe like is encountered by the auger. In the event the auger encountersa boulder or other localized impediment to its further progress alongaxis 30 or 78, the auger may follow along the normally curved surface ofthe boulder until it has moved to the side of the boulder, The auger maythen continue to burrow downwardly past the boulder, although it may nowfollow a. path which lies at an angle to its path before the boulder wasencountered,

As described above, the penetrometer is instrumented. so that;measurements of: the torque delivered to the flexible shaft, and thus tothe auger, are continuously oh tained, Also, measurements of theinstantaneous depth of the auger in the soil formation are continuouslyob tained via the potentiometer coupled to the flexible shaft coilingmeans; these measurements are also useful to in.- dicate the rate ofadvance of the auger, From a knowledge of the torque required to drivean auger of known char acteristics through a. soil formation. at aparticular rate, the load bearing and density characteristics of thesoil may be determined, Moreover, the shear strength of the soil at anydepth may be determined. by stopping rotation of the flexible shaft andpulling upwardly on the flexible shaft until the auger moves axially inthe soil, The auger is pulled upwardly by positively locking slip clutch47 (or 109) to motor 46 (or 110) and increasing the power to theflexible shaft tensioning and reeling motor: The poll. on. the flexibleshaft is measured by strain gages 51 as the coiling and drive assemblymoves relative tothe base from. which it is cantilevered Thereafter,rotation 7 of the flexible shaft may be resumed to drive .Lht'; auger toa. deeper locationv in the soil formation.

The auger may be recovered from the soil formation merely by reversingthe operation of motors 42 and 46, or motors 86 and. H0, as the case maybe As shown. in, FIG. 5, a flexible shaft. fabricated 01''? severalconcentric spirally wound wires (adjacent spirals being wound inopposite directions) has a hollow core passage 120. The flexible shaft,therefore, may be used as a. conduit: for electrical conductors from theauger to the flexible shaft coiling and stora emeans. Accordingly ifdesired, the torque delivered to the auger and the ten sion on heflexible shaft may be measured at the auger merely by equipping theanger with suitable in rument transducers designed to sense suchquantities. Such trans ducers are "Within. the present. state of theinstrumentation art and form. no part. of the present invention per seand thus such an alternative to the ahovedescribed structure is notillustrated, although the means whereby such an alternative may beaccomplished will be readily apparent to markets skilled the art towhich the present inven tion relates. It is only necessary to provideadditional slip ring and brush combinations in the electrical connectionof the coiling meanssupport member to the frame so that signals from thetransducers may be obtained at the frame or the base of thepenetrometett Moreover, if? desired, the augermay be equipped withadditional transducers and measuring devices whereby ad ditionalmeasurements of desired characteristics or" the soil formation may beobtained. For example, thermocouples radiation counters, moisturesensors, magnetic sensors and the like may be housed in auger body 22,and the conductors by which the output signals of such devices aresupplied to the surface of the soil formation may be passed through corepassage 120 of the flexible i shaft. A penetrometer augmented with suchinstruments is useful in prospecting for minerals or water, as well asin obtaining measurements of the structural characteristics of soil.

The instrumentation of penetrometers l0 and 70 for measuring torque andtension in the flexible shat here of may be eliminated where it isdesired to provide apparatus for burrowing into a soil formation to proide an anchor in soils or in soils under water, In view of this utilityof structure according to this invention, and also in View of the ruggedconstruction of such structures, it. is apparent. that. the inventionmay be useful in. manned. and unmanned explorations of the moon, forexample Apparatus instrumented in accord withv the foregoing:

description may e included in a space vehicle designed for a soft (the,non-destructve) landing on the moon The auger may be operated to cuaseit to burrow into the lunar soil so that measurements of certaincharacteristics of the soil may be obtained. The output. signals fromthe instruments the apparatus can applied to a telemetry system in thevehicl for ransmission to earth for interpretation and analysis. Afterthe auger has bur rowed into the lunar sod, it may serve as an anchor sothat the vehicle becomes a stable:- platform. upon "which or from. whichother experiments, such Seismological experiments may be conducted.

From. the foregoing, it. is apparent that this invention. provides a.versatile, rugged and effective apparatus for burrowing into a soilformation. The invention may be used for any one of a number ofpurposes, depending upon. Whether and how it is instrumented Theinvention has been described abov in the context of. a soilpcnetrometer, but such a form of the invention has been selected merelyfor the purposes of explanation and example to one skilled in the art.to which the invention relates Such workers will readily appreciate thetrue scope of the in vention and will understand that alterations andmodifica" tions may be made in the structures above-described with outdeparting from the true scope of the 'lU CUlIQ Ar" -cordmgly. it as tobe understpnrl Ihal Lhrji ventio cludes the reasonable equivalents oithe structures and procedures described, and is not to be restricted tothe presen ly preferred embodiments selected for presentation herein.

What is claimed .55 1 Apparatus. for burrowing into a soil formation comprising a) an elongate coilable torque transmitting member, t'b) coilingmeans for the torque transmitting member at one end of the torquetransmitting member, to) an auger connected to the other end of thetorque transmitting member to be driven in response to ro tation of thetorque transmitting memben, td) a base adapted to he supported on thesurface of soil formation v (e) support. means for the coiling meansmounted to the base for rotation relative to the base,

the torque transmitting member extending from the coiling means to theauger along the axis about. which the support. means is rotatable rela--tive to the base, and it) drive means coupled. to the support means operable to rotate the support means about said axis to rotate the torquetransmitting member thereby to drive the auger 2. Apparatus according toclaim l wherein the coiling means comprises a hollow conicallyconfigured cage disposed above the base and aligned with said axis, thecage having its small end disposed downwardly and opening along saidaxis,

3. Apparatus according to claim 2 wherein the support means includes arotatable member mounted to the base for rotation about. said axis anddisposed between the base and the cage, the lower end of the cage beingsecured to the rotatable member concentric to said axis for rota tionwith the rotatable member about said axis, the rotatable membet defininga passage therethrough along said axis through. which the torquetransmitting member ex-- tends from the cage to the auger 4. Apparatusaccording to claim 3 wherein the drive means comprises a gear secured tothe rotatable member concentric to said axis, a motor mounted to thebase and having a rotatable output shaft, and gear means intercon nectedbetween the motor shaft. and the gear for rotating the gear and therotatable member about said axis in response to operation of the motor.

Apparatus according to claim 3 including means for reeling the torquetransmitting member into and out of the cage.

6, Apparatus according to claim 5 wherein the reeling means includes adrive pulley rotatably mounted to the rotatable member and engaged withthe torque transmitting member aiong saidv passage. an idler wheelengaged with the torque transmitting member and rotatably mounted o therotatable member opposite the torque transmitting membe rotn the drivepulley, and a motor coupled to the drive pulley for rotating the same.

Apparatus according to claim 6 including a slip coupling connectedbetween the reeling means motor and the drive pulley permitting relativemotion between the pulley and the motor so that the motor may be drivenin the same direction as but slower than advancing move-- men of theauger as the torque transmitting member is payed out. from the cage tomaintain tension on the torque transmitting membe as the auger 1Sadvanced, and so that the motor can be driven in the same direction butfaster than retreating movement o the anger as the torque transmutingmember lS reeled into the cage to maintain tension on the torqueransmitting member as the auger is re-- covered.

8. Apparatus according to claim l wherein the coiling means includes.drum mounted to the support. means to! rotation about a. second axisnormal to the axis about which the support means is rotatable relativeto the him 9, Apparatus according to claim 8 wherein the drive meansincludes a gear secured to the support means con centric to the axis ofrotation of. the support means, a motor mounted to the base and having arotatable output shaft, a gear means interconnected between the motorshaft and the gear for rotating the gear in response to operation of themotor,

10, Apparatus according to claim 8 including means for reeling thetorque transmitting member to and from the drum and for maintainingtension on the torque transmitting member during reeling thereof to andfrom the drum,

11, Apparatus according to claim 10 wherein the reel-- ing andtensioning means includes a motor mounted to the support means forrotation with the support means relative to the base, the motor having arotatable output shaft and a slip coupling connected between the motorshaft and the drum for rotating the drum in response to operation of themotor and for allowing the drum to rotate at a rate different from thatcorresponding to the operational rate of the motor in response to loadsimposed upon the drum,

12, Apparatus according to claim 1 including means for reeling thetorque transmitting member to and from the coiling means and formaintaining the torque transmitting member in. tension during rotation.of the torque trans mitting member 13.- Apparatus according to claim 1,including means for receiving and for guiding the auger into engagementwith the soil formation along a selected path.

14. Apparatus according to claim 1 including means for measuring thetorque imparted to the torque transmitting member.

15. Apparatus according to claim 14 including means for reeling thetorque transmitting member to and from the coiling means and formaintaining the torque transmitting member in tension during rotationthereof, and means coupled to the torque transmitting member operableduring rotation thereof for measuring the tension therein.

16. Apparatus according to claim 15 wherein the torque transmittingmember comprises a flexible shaft, and means for continuously measuringthe amount of flexible shaft reeled out from the coiling means,

References Cited UNITED STATES PATENTS 2,930,137 3/1960 Arps 731513,092,181 6/ 1963 Alexander 73-151 3,153,339 10/1964 Alexander et al73151 3,331,240 7/1967 NilsSon et a1, W 7384 RICHARD C. QUEISSER,Prinmry Examim'r.

JAMES GILL, Examiner:

lRVlN (3, MCCLELLAND, Assistant Examiner.

1. APPARATUS FOR BURROWING INTO A SOIL FORMATION COMPRISING: (A) ANELONGATE COILABLE TORQUE TRANSMITTING MEMBER, (B) COILING MEANS FOR THETORQUE TRANSMITTING MEMBER AT ONE END OF THE TORQUE TRANSMITTING MEMBER,(C) AN AUGER CONNECTED TO THE OTHER END OF THE TORQUE TRANSMITTINGMEMBER TO BE DRIVEN IN RESPONSE TO ROTATION OF THE TORQUE TRANSMITTINGMEMBER, (D) A BASE ADAPTED TO BE SUPPORTED ON THE SURFACE OF SOILFORMATION, (E) SUPPORT MEANS FOR THE COILING MEANS MOUNTED TO THE BASEFOR ROTATION RELATIVE TO THE BASE, THE TORQUE TRANSMITTING MEMBEREXTENDING FROM THE COILING MEANS TO THE AUGER ALONG THE AXIS ABOUT WHICHTHE SUPPORT MEANS IS ROTATABLE RELATIVE TO THE BASE, AND